<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        html,body{
            margin:0;
            padding:0;
            height: 100%;
        }
        .addDom{
            box-sizing: border-box;
            border:1px dashed #aaa;
            position: absolute;
        }
        .father{
            width:50%;
            height:600px;
            /* position: absolute;
            top:200px;
            left:200px; */
        }
        .resizeBtn{
            width:6px;
            height:6px;
            background: chartreuse;
        }
    </style>
</head>
<body>
    <button id="add">
        实例化
    </button>
    <button id="clear">
        销毁
    </button>
    你好啊哈哈哈哈哈哈哈哈哈哈
    <input type="text">
    <div class="father">
        
    </div>
</body>
</html>